Stoker hopper switch



sept. 27, 193s.

B. E. SHAW 2,131,305

STOKER HOPPER SWITCH Filed April 27, 1937 Patented Sept. 27, 1938 I AUNITED' lsm'rlzs PATENT or-FlcE s'roxnn norma swrrcn v1mi-imi n. shaw, adel, Iowa, assignmto Penn A i meen-1a switch ne: Moines, Iowa. a wparatinnot Iowa application apra 221, 1937. semen.` 139,251

` an object of my present .invention is to provide Y a stoker hopper switch which is readily adaptable for mounting on the hopper o! a stoker `for controlling a fuel Isupply means. 5. A further obiect is to provide a switch especially adaptable for stoker hopper yoperation and including means responsive to the presence or absence of fuel in the hopper to control a circuit. Another object is to provide a switch so designed that it can be readily adjusted for installation of various types, and particularly can be changed on the job from a switch which is closed when fuel is present in the hopper to one which is closed when there is an absence of fuelin the hopper, or vice versa, in a facile manner.

A further object is to provide a switch particularly adaptable for hopper installation including a reversible cam and means to operate the cam including a rock shat and a pressure plate carried thereby and extended into the hopper i'or operation by coaction of,coal or other fuel inthe hopper therewith.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my stoker lhopper switch, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

. 80 Figure l is a diagrammatical sectional View through a hopper and a feed bin therefor showing my hopper switch installed for operating a fuel conveyor lfrom the bln to the hopper.

Figure 2 is a front' elevation of same looking in the direction of the arrow 2l adjacent Figure 1.

Figure 3 is an enlarged sectional view .on the line 3 3 oi. Figure l showing a pressure plate or blade used in connection with my hopper switch for actuating the same. 49 Figure 4 is an enlarged sectional view on the line l-I o! Figure 2. Figure 5 is a sectional view on the line 5-5 of Figure 4 showing the parts on a reduced scale and showing the cam of the switch mechanism 46 adjusted for operation in the circuit shownin Figure l.

Figure 6 is a perspective view of an actuating member of my switch mechanism to which a cam member is to be secured. Figure 'l is a perspective view ot the cam member.

Figure 8 is a sectional diagrammatic-,al view of a stoker with my hopper switch mounted thereon for operation in a dlil'erent type ot circuit:

and

Figure 9 is a view ofthe actuating'member and cam of Figures 6 and 'I showing the fcsm reversed relative to the position shown inligure 5 for operation in the ycircuit shown in Figure l.

0n the accompanying drawingl havensed the:y reference character' H to indicate a hopper of a stoker or the like,andB a binadapted tooontain coal or other fuel to be fed t0 the hopper H. I show ditically a screw conveyor II for conveying the fuel from the bin B to the hopper l0 H, the conveyor being operated by a motor l.

My hopper switch includes a rock shaft I l suitably journalled in bearings I2 attached to a I3 of the hopper H. The wall may be slotted as at I4 to permit the passage of a pressure plate v I5 therethrough, the pressure plate I5 being se cured at its outer edge to the rock shaft Ii. As shown in Figure 3, the pressure plate Il is adapted to normally assume a position spaced from the wall I3. Such position is shown by solid lines. l0

In `Figure 2 I show a spring Il for biasing the pressure plate I5 to such. position, the siting being connected with a lever I1 imountedon the rock shaft II. Whenever suiilcient fuel is present in the hopper H to cover plate Il, the 2 5 plate will be moved to the dotted position shownv in Figure 3 against the bias of the spring Il.

I provide a switch indicated generally at B adapted to control the motor M and responsive to the movement of the shaft Ii and consequently,A $0 the pressure plate I5. The switch E includes a protecting casing I8 mounted as by a bracket Il on the hopper H. Within the casing il a bracket 20 is provided on which is mounted a switch hous-` ing 2i having a cover plate 22. 85

-Within the switch housing an armature Il'is pivotally mounted and carries an armature 25 adapted to be attracted by a permanent magnet 25. yWhen-the armature 23 is in the position shown in Figure 4, it separates a pair of contacts i0 26 and 21 from each other, which contacts are included in the circuit of the motor M.

' For actuating the armature arm 2l, and thereby opening and closing the contacts, 2l and 21 I provide an actuating element in the form of a 45 slidable pin 28. A spring 2l is interposed between this pin andthe armature 2l for absorbing part of the energy which slides the pin and storingsuch energy for quickly moving thearmature 2l from adjacent the magnet 25 and thereby .IODG- 50 rating the contact 25 from the contact 21 with snap action.

A cam C is provided for operating the pin 2l. This cam' has a 'lobe 3U, an arcuate slot I2 and a vhub. Thehublismolmtedonamvotlln 34 supported by the bracket 20 and is connected with an actuating lever 35. The lever 35 is likewise mounted on the pin 34 and the two are secured together by an adjusting screw 36. This screw is threaded into one or the other of a pair of threaded openings 31 and 38 in the actuating lever 35. The actuating lever 35 has a slot indicated at 3S with which a pin 4d im adapted to coact. The pin lli is carried by the arm l'i secured as by a set screw i2 to the rock shaft il.

Practical operation the dotted position of Figure 3, due to the presence of fuel in the hopper H.

Thus the motor M and conveyor lll will be stopped whenever the hopper H is filled with fuel and will be started as soon as the fuel recedesin the hopper to a position below the plate 15,.

whereupon the spring I6 will swing the plate to the full line position and again initiate'operation of the conveyor I0, which will continue to operate until the` hopper is again filled. The particular position of operation of the switch relative to the position of the plate I5 can be adjusted somewhat by the adjusting screw 36 and arcuate slot 32.

In Figure 8 an installation is shown wherein a hopperH' is customarily fed with fuel from a source of supply including a chute 43. A motor M operates the blower and fuel feeding mechanism of a stoker 44 and is controlled by a `room thermostat RT and a switch S in series.

The cam C for this installation is reversed as illustrated in Figure 9 when compared with Figure 5, so that when the hopper H has been emptied, the switch contacts 26 and 21 will be separated instead of engaged. Thus the switch S in the installation in Figure 8 serves as a safety switch to cut off the supply of current to the motor M which is normally controlled in response to room temperature, and such cut 01T occurs whenever the supply of fuel is exhausted or-runs low in the hopper H This provides assurance against the blowing back of coal from the stoker 44 into the hopper H as would occur when the coal is almost completely fed into the furnace and the'motor M' continues to operate, thus creating a pressure above atmospheric pressure in the furnace, Stoker and hopper.

I have provided a switch which, it is obvious, can be readily adjusted for either of the installations shown in Figures 1 and 8, or for any other installation suitable where a pressure plate may be utilized within a hopper or the like to control the switch.

It is a comparatively simple matter to remove the screw 36, for instance, from'the opening 38,

turn the cam C a half revolution and then reinsert ther screw in theopeningvll.

Some changes mayv be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and itis my intention to.

cover by my claims any modified forms of strucescasos ture or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

ll. Inastoker hopperswitch, a rock shaft, a plate having one edge connected therewith, means biasing said rock shaft to rotate and project the tree edge of said plate into the stoker hopper, a control switch -and an operative connection between said rock shaft and said control switch, said control switch including a casing and an operating element projecting therefrom for the switch mechanism of the control switch, a movable actuator having a cam lobe coacting with said operating element.

2. In a stoker hopper switch, a rock shaft :lournaileol on the wall of a stoker hopper, a plate having one edge connected therewith, means bi- -asing said rock shaft to rotate and project the free edge of said plate into said hopper, a control switch and an operative connection between said rock shaft and said control switch, said control switch including a movable actuator, a cam member reversibly mounted thereon and an operating element for the switch mechanism of said control switch and coacting with said cam member in either of its reversed positions. ff

3. In a device of the class described, a rock shaft, a pressure plate connected thereto, a switch for operationby said rock shaft and having an operating element, a cam coacting therewith and means for actuating said cam comprising a lever and a second lever mounted on said rock shaft and having a pin and slot connection with said first lever.

4. In a device of the class described, a rock shaft. a pressure plate connected thereto, a switch for operation by said rock shaft and having an operating element, a cam and an operative connection between said rock shaft and said cam,

said cam comprising a disk having a lobe axially displaced from the plane of the disk and coacting with said operating element to move it axially of said disk 5. In a device of the class described, a movable pressure plate adjacent the wall of a hopper, a switch for operation thereby and including a housing and an operative connection between said pressure plate and said switch for operating said switch in accordance with movements of the pressure plate in response to the pressure of fuel thereagainst in said hopper, said operative connection including a rock shaft, a lever attached thereto and terminating adjacent said housing,

said switch having an operating element projecting from said housing and having a pin and slot connection with vsaid lever. Y

6. In a. stoker hopper switch, a rock shaft, a pressure plate connected therewith, a switch having an operating element, a disk like cam for actuating said operating element and having an axially displaced lobe and an operative connec- 'r tion between the rock shaft and said cam, said cam being reversible to place said lobe on the radially opposite side of the axis of said disk for reversing the operation of said switch in response to movement of said pressure plate.

7. In combination with a stokerhoppenaswitch operable in response to the presence of 'fuel therein, fuel supply means controlled by said switch, said switch including a reversible cam for actuating the switch mechanism thereof whereby said cam may be installed for either opening or closing the circuit of said fuel supply means in response to the presence of fuel in said hopper. i

BURTON E. SHAW. 

